On Fri, Feb 13, 2009 at 06:41:35AM +0000, Al Viro wrote:
Aaaargh...
/*
* We don't have to hold all of the locks at the
* same time here because we know that we're the
* last reference to mnt and that no new writers
* can come in.
*/
for_each_possible_cpu(cpu) {
struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu);
if (cpu_writer->mnt != mnt)
continue;
spin_lock(&cpu_writer->lock);
is *almost* OK. Modulo SMP cache coherency. We know that nothing should
be setting ->mnt to ours anymore, that's fine. But we do not know if
we'd seen *earlier* change done on CPU in question (not the one we
are running __mntput() on).
I probably would still like to use milder solution in the long run, but for
now let's check if turning that into
struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu);
spin_lock(&cpu_writer->lock);
if (cpu_writer->mnt != mnt) {
spin_unlock(&cpu_writer->lock);
continue;
}
prevents the problem, OK?
_______________________________________________
Containers mailing list
contain...@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/containers
_______________________________________________
Devel mailing list
Devel@openvz.org
https://openvz.org/mailman/listinfo/devel
